Category Archives: YPM

Map of the YPM galleries as they are currently arranged. North is right.

The dinosaur and fossil mammal halls at the Yale Peabody Museum of Natural History (YPM) closed on January 1st of this year. In the last post, I covered some of the exhibition’s history, with a focus on the mounted dinosaur skeletons that won’t be returning when the halls reopen in 2023. This time, I want to explore what the new paleontology exhibits might be like. To be clear, I don’t have any privileged information about the YPM renovation. I only have my own insight from working on exhibits at other museums, and my immoderate interest in historic fossil displays (see the rest of this website). Fortunately, YPM staff have been very generous with news about the project, and there is even a dedicated website with details about the renovation. Let’s see how much we can piece together.

As I touched on in the previous post, this renovation has been a long time in coming. Few significant changes had been made to the paleontology halls since the 1950s, and these spaces are in many ways time capsules from another era—both in terms of paleontological science and exhibit design. Serious conversations about redeveloping the dinosaur and mammal halls were underway by 2010. During this process, the team noted the disjointed nature of the existing exhibits, which had been installed on an ad hoc basis. For instance, a visitor moving along the west side of the dinosaur hall would encounter modern crocodilians, Triassic trees, and a Cretaceous mosasaur, before passing into the fossil mammal hall and encountering a Quaternary mastodon. These random jumps back and forth through time undoubtably made it difficult for visitors to make much sense of what they were seeing, beyond a menagerie of old dead things.

Seeking to unify the fossils on display within a single, cohesive story, the team proposed a variation on the traditional “walk through time.” Rather than dividing the space into segmented galleries based on the formal divisions of geologic time, the emphasis would be on broad-scale environmental changes. This presentation would synergize with the existing Rudolph Zallinger murals. The 110-foot TheAge of Reptiles (completed in 1947) and the 60-foot TheAge of Mammals (completed in 1967) are epically-scaled frescos that show the evolution of life over time without hard boundaries. Instead, flora and landscapes from different time periods blend seamlessly into one another. In the same way, the proposed exhibition would present its narrative holistically, encouraging visitors to track the underlying environmental trends that precipitated evolutionary changes. As I discussed some time ago, this is not dissimilar from the approach taken for Deep Time.

The Hall of Mammal Evolution in 2014. Photo by the author.

These discussions must have been the basis for the set of concept images released alongside the launch of a new fundraising effort in 2013 (why they needed to fundraise when Yale has a $30 billion endowment is beyond me—I promise this will be my only snarky aside about that). Architectural firm Studio Joseph envisioned wide-open and well-lit spaces, in which the grey carpet and grid-patterned walls were replaced by bright earth tones accentuated by ash wood panels. A mezzanine on the west side of the dinosaur hall would have allowed visitors to view The Age ofReptiles directly, rather than from the floor. A long, continuous case directly beneath the mural would contain fossil specimens that directly corresponded with the scene above.

In the center of the hall, remounted Brontosaurus and Stegosaurus skeletons were to be joined by a brand-new Allosaurus, shown attacking the Stegosaurus. In the concept images, the dinosaur skeletons are directly on the floor, rather than on platforms. Barely-visible glass barriers prevent visitors from getting too close to the specimens. In the background, the Beecher Edmontosaurus is in the same position it’s held on the north wall since 1925. A mosasaur attacking an Archelon appears to be suspended from the ceiling in the northwest corner.

The 2013 mammal hall concept follows the same aesthetic principles as the dinosaur hall. The space-hogging floor-to-ceiling cases are gone, replaced by the same circular glass barriers shown around the dinosaur mounts. Whereas the old hall was loosely organized around a mid-century understanding of evolutionary relationships, this new version would be strictly chronological. The old fundraising page lists a Megacerops display, a Moropus display, and a mastodon display, and indeed, those skeletons appear to anchor the three major areas portrayed in the concept image. One can imagine these early, middle, and late Cenozoic tableaus illustrating the climactic shift from warm and wet to cool and dry. Oddly, the arrangement shown here runs in the opposite direction of The Age of Mammals mural, in which the ice age is on the west side of the hall.

But all that was seven years ago. Near as I can tell, everything changed when Yale alumnus Peter Bass made a $160 million donation, apparently the largest single gift ever made to an American natural history museum. YPM also changed directors—in 2014, freshwater ecologist David Skelly took over the position from geologist Derek Briggs. The renovation is no longer limited to the two paleontology halls, but will encompass the entire museum—and more. Over the next four years, the YPM and surrounding area will gain a north courtyard and new museum entrance, a dedicated entrance and gathering area for school groups, a multi-story lobby connecting YPM to the academic building next door, new collections and research facilities, new classrooms, 50% more exhibit space, and a 500-seat lecture hall named for O.C. Marsh.

Centerbrook Architects and Planners—a company already responsible for twelve other projects on the Yale campus—was hired to continue the design process. Centerbrook’s renders (and a video flythrough) are available on the Peabody Evolved website. At this stage, it’s difficult to tell which parts of these renders represent real plans and which parts are placeholder. For the purposes of this discussion, I’ll be taking the renders at face value, but will note when something might be merely suggestive of a to-be-determined element.

It’s clear is that after the renovation, fossil displays will range far beyond the dinosaur and mammal halls. Some of these are already complete: in August 2019, a crew from Research Casting International moved a Triceratops skull and a relief-mounted Pteranodon from their traditional home in the dinosaur hall to the lobby of the new Marsh lecture hall (part of the recently-completed Yale Science Building to the north of the museum). Meanwhile, the Centerbrook plans shows a mosasaur to the left of the new north entrance to YPM. It’s the approximate size and shape of the Platecarpus skeleton in the old dinosaur hall, so perhaps that fossil will be relocated, as well.

At the heart of the renovated museum will be the central gallery, a brand-new structure filling in an empty space between the YPM and the Environmental Science Center to the east. It will run parallel to the dinosaur hall, sharing a wall on the existing gallery’s west side. Although the overall design is quite modern, the scale and color palette of this new 4-story space is meant to complement the French Gothic revival architecture of the original museum building. Lit by a skylight and filled with comfortable seating, the designers hope that the central gallery will be a space for students and museum visitors to relax and co-mingle, better integrating the museum into the campus community.

Flying high over people’s heads will be battling Archelon and Tylosaurus skeletons. You’ll remember that this scene was originally envisioned for the dinosaur hall. Relocating these skeletons to the central gallery gives them far more room to spread out. The Archelon in question is the holotype (YPM 3000), which was collected in 1885 in South Dakota. Measuring 15 feet across, this Cretaceous sea turtle has been on display since the turn of the 20th century. Given that it will be suspended an inaccessible 30 feet in the air, this new version of Archelon will almost certainly be a cast. The Tylosaurus is reportedly a specimen from the YPM collection that has never been displayed before.

That brings us to Centerbrook’s revised take on the dinosaur hall. Several elements of the Studio Joseph design are still in evidence: the remounted Brontosaurus is at the center of the gallery, the Edmontosaurus remains on the north wall, and the specimen cases below the Zallinger mural are arranged in sync with the artwork above. Nevertheless, many changes have clearly been made. The ash wood panels are gone, and the walls are now austere white. The mezzanine is out, along with the battling Stegosaurus and Allosaurus. The Archelon and Tylosaurus are missing, of course, but we know that they’re in the central gallery. I imagine that these cuts have less to do with money than with real estate: once designers started laying out the proposed elements in 3-D space, it became clear that there was no way everything would fit.

I see five major sections in this version of the dinosaur hall. First is the curved wall, which faces visitors when they enter the exhibit from the south, or from the central gallery. The render shows ammonites on the south side of this wall, but these might be placeholder images. I expect this area to be an introduction to the exhibition and its organization.

On the opposite side of the curved wall and hidden from immediate view is Stegosaurus (YPM 1853), a companion to YPM’s famous Brontosaurus (YPM 1980). We can call this the Jurassic dinosaurs section, which occupies most of the floor space. Both dinosaurs were recovered around 1879 by William Reed’s field crew at Como Bluff, Wyoming, and were subsequently described by Marsh. Richard Lull (who called it “the most grotesque reptile the world ever saw”) oversaw the construction of the Stegosaurus mount in 1910. The great hall was specifically designed to fit the Brontosaurus, which was completed in 1931. Both of these historically-significant specimens will be restored and remounted for the new exhibition. Brontosaurus is afforded a large platform with built-in seating. The designers have included plenty of space for visitors around this star attraction, allowing for plenty of photo opportunities. It’s disappointing that Stegosaurus is no longer fighting Allosaurus (this hall could use a large theropod or two), but it’s not like we can’t see similar scenes at other museums.

The view upon entering the dinosaur hall from the central gallery. Source

A row of cases under The Age of Reptiles appears to be arranged chronologically, with fossil specimens directly corresponding with the mural overhead. On the south end of the east wall, I see YPM’s complete Limnoscelis and the fin-backed Edaphosaurus. In the old hall, Edaphosaurus was mounted in relief, but this render shows a three-dimensional mount. I’m assuming the wire-frame theropod shown under the Cretaceous portion of the mural represents a Deinonychus mount. Including Deinonychus is a must, of course, since John Ostrom did his groundbreaking work demonstrating the theropod origin of birds at YPM. There is a smaller row of a cases on the west wall, and the only specimen I can make out appears to be YPM’s swimming Hesperornis mount. Perhaps this section is about the evolution of marine life, while the displays directly under the mural are about terrestrial life.

Finally, the relief-mounted Edmontosaurus anchors the Cretaceous dinosaurs section at the north end of the hall. Built in 1901, this is the oldest surviving dinosaur mount in North America. Contrary to the common narrative that all early 20th century paleontologists saw dinosaurs as cumbersome tail-draggers, this mount is downright sprightly, and could be mistaken for a reconstruction from the last 20 years. As such, it’s fitting that Edmontosaurus should remain in its original form. Since the Edmontosaurus was installed in the great hall in 1925, the space in front of it was gradually filled with a myriad of dinosaur skeletons, skulls, and models. In the new exhibition, this will be simplified to feature the skulls of three Edmontosaurus contemporaries: Triceratops, Torosaurus, and Tyrannosaurus.

The new dinosaur hall as seen facing south. I think this render is slightly older than the images above. Source

Although no new images of the mammal hall have been shared yet, there is a telling change visible in the dinosaur hall renders. Currently, the doorway between the two fossil halls is on the west side of the north wall, but the new plans show it moved to the east side (there used to be a door there, but it’s been buried behind exhibit cases for decades). Relocating that door means visitors will enter the mammal hall in the center, and have the choice to move to the left or to the right. Presently the only other entrance to this space is from the human evolution gallery to the east, but perhaps once the central gallery is built the emergency exit to the left can become a regular passageway. What all this means for the content is anyone’s guess. On option would be to place the mounts on a central island—then visitors could circle counterclockwise and generally follow the Zallinger mural (which runs east to west) through time.

One thing these images tell us nothing about is media and interactivity—important parts of many contemporary exhibitions. Speculating wildly for a moment, I think it would be incredible if YPM used projection mapping or similar technology to create a media presentation directly on The Age of Reptiles. I’m imagining something vaguely like a planetarium show, with either pre-recorded or live narration. The show could illustrate how the mural was created, projecting an animated Zallinger on his ladder, looking tiny against the massive canvas. It could also portray the animals in motion, or provide us glimpses of modern reconstructions of the more outdated creatures. A show like this might draw more visitors to pay attention to the mural and appreciate its historical significance.

Research Casting International—the leading company specializing in preparing and mounting fossil skeletons—started work at YPM on January 20th. The crew has already dismantled several of the dinosaur skeletons, which will travel to their workshop outside Toronto for restoration, and in some cases, remounting. After that, we have a three year wait until the new YPM opens. I guess we’ll see then how many of my predictions here hold true.

Another year, and another major renovation of a historic paleontology exhibition is underway. The dinosaur and fossil mammal halls at the Yale Peabody Museum of Natural History (YPM) closed to the public on January 1st. The rest of the museum will follow in July, with a planned reopening in 2023. This will be the first comprehensive renovation of the museum since the current building opened in 1931, and the upgrades are long overdue. For decades, most of the YPM exhibits have been a museum of a museum—a time capsule preserving the state of natural science and museum design in the mid-20th century. The dinosaur hall in particular looks almost exactly as it did when Rudolph Zallinger completed the spectacular Age of Reptiles mural on the east wall in 1947 (a handful of newer specimens, revised labels, and video terminals notwithstanding).

The Great Hall of Dinosaurs upon my last visit in 2014.

It’s exciting to see ground breaking on the new museum and exhibits, because this renovation has been a long time in coming. Serious discussions were underway in 2010, if not earlier, and a set of conceptual images was released as part of a fundraising effort launched in 2013. It appears that a lot has changed since then. The scope of the renovation has expanded to encompass the whole museum, not just the paleontology exhibits. And certain details from the 2013 concept—such as a mezzanine in the dinosaur hall opposite the Age of Reptiles mural—have been dropped. Last year, YPM launched a dedicated website showcasing the latest renovation plans. It’s wonderful that the institution is committed to keeping their community involved in and informed about the transformation of a public space that is near and dear to so many.

Naturally, this renovation is an opportunity to take a deep dive into the YPM fossil displays, and look at the specimens, artwork, and people that defined this institution in the past and which will carry it into the future. Expect upcoming posts exploring the future of these exhibits, but for now let’s start with a look back at the exhibit that once was.

YPM was founded in 1866 with a gift from George Peabody. Peabody was the uncle of O.C. Marsh, who had been appointed Professor of Vertebrate Paleontology at Yale that same year. Having been awarded tenure and his own museum, Marsh began to lead and send crews into the American west to collect fossils. Many of Marsh’s expeditions were under auspices of the U.S. Geological Survey, and those fossils eventually made their way to the Smithsonian. The remainder, however, entered the YPM collections, where they remain to this day.

After Marsh’s death in 1899, his student Charles Beecher took over vertebrate paleontology at YPM. Beecher was, in turn, succeeded by Richard Lull. Lull never met Marsh (and the two were quite different in many ways), but he nevertheless spent much of his career carrying on his predecessor’s legacy. Like his Smithsonian counterpart Charles Gilmore, Lull expanded Marsh’s often laughably brief descriptions into proper monographs, which are still used by paleontologists today. And like Gilmore, Lull put the Marsh fossils on public display, guiding the assembly of the mounted skeletons that have held court at YPM ever since.

Lull became director of YPM in 1922, and it was in this role that he oversaw the museum’s move from it’s modest original building to the larger, French Gothic-inspired structure where it currently resides. Construction of the new museum was completed in 1925, and Lull spent the next several years developing the dinosaur hall we know today. Marsh, for his part, disliked the idea of display mounts, considering it a waste of time and effort. And limited space at the old facility meant that only two large dinosaur mounts—Edmontosaurus and Stegosaurus—were assembled between 1900 and 1925. The new building, however, had a great hall specifically built to house the Marsh dinosaurs, so Lull and his team got to work filling it.

Camarasaurus and Camptosaurus

Camarasaurus and Brontosaurus mounted skeletons.

Most of the new mounts were assembled from fossils collected around 1880 at Como Bluff, Wyoming. Working for Marsh, William Reed and his crew amassed a treasure trove of Jurassic dinosaurs there, most famously the Brontosaurus holotype. Naturally, Lull devised Brontosaurus (YPM 1980) as the centerpiece of the dinosaur hall. Because of its size and complexity, it was the first of the new mounts to begin construction and took the longest to complete. The Brontosaurus was literally built into the floor: photos from the 1920s show a latticework of steel beams designed to spread its weight. Once the floor was installed, the Brontosaurus could not be moved.

In the meantime, preparator Hugh Gibb assembled two other mounts from Como Bluff material: Camarasaurus and Camptosaurus. The Camarasaurus (YPM 1910) is 21-foot juvenile, consisting of a complete vertebral column from the 2nd or 3rd cervical to middle of the tail, and most of the larger limb bones. The feet and most of the ribs are reconstructed, as is the skull, which is a fairly crude sculpture. In his 1930 publication discussing the mount, Lull commends Gibb for how closely his reconstruction matched the nearly complete and articulated juvenile Camarasaurus collected by the Carnegie Museum at what is now Dinosaur National Monument, despite the fact that Gibb had never studied that specimen. Lull only notes that the YPM mount has one fewer cervical and one fewer caudal than the Carnegie specimen, and that the reconstructed cervical ribs are much too short.

Camptosaurus and Camarasaurus mounted skeletons.

Gibb also assembled the Camptosaurus mount (YPM 1880), which he completed in 1937. Yet another specimen from Reed’s excavations at Como Bluff, the Camptosaurus is notable for how closely it mirrors Marsh’s illustrated reconstruction from 40 years earlier. It seems reasonable to assume this was a deliberate homage, although Gibb did follow Gilmore’s example and removed Marsh’s erroneous lumbar vertebrae. The sculpted skull, modeled after Iguanodon, was typical of Camptosaurus reconstructions at the time but is now known to be inaccurate.

Neither Camarasaurus nor Camptosaurus are slated to return in the renovated exhibit. Marsh originally designated both of these specimens as holotypes for “Morosaurus” (=Camarasaurus) lentus and Camptosaurus medius. Opinions on the validity of those particular species have changed over time, but it’s important that a new generation of paleontologists has an opportunity to study the original fossils up close, which has been virtually impossible in their mounted form.

Claosaurus

Relief mount of Claosaurus.

High on the west wall is one of YPM’s most overlooked dinosaurs. This relief mount represents the only confirmed remains of Claosaurus agilis (YPM 1190), a hadrosaur found in the marine deposits of western Kansas. Claosaurus is a bit of a taxonomic mess: Marsh initially announced this fossil as a new species of Hadrosaurus, before upgrading it to its own genus. Then, he decided to sink all of the much younger Lance Formation hadrosaur material (what is now called Edmontosaurus annectens) into the Claosaurus genus. It’s a difficult web to untangle, but Claosaurus is a real taxon that lived alongside animals like Pteranodon and Tylosaurus.

Lull and Wright describe the mount as “recent” in their 1942 monograph on hadrosaurs, so it must have been assembled after the move the current building. Most of the vertebrae and limb bones are real, but the skull is (obviously) a model built around a few fragments of jaw. Although it’s hard to see from the ground, the preservation is apparently poor, and most of the bones are crushed to some degree. Lull and Wright attest to the significance of Claosaurus as the earliest known true hadrosaur, but were clearly frustrated by the quality of the specimen. Perhaps modern paleontologists will have better luck, once it’s taken off display and returned to the collections.

Centrosaurus

The Centrosaurus half-mount and its Cretaceous buddies.

Variably known as Monoclonius flexus, Centrosaurus flexus, and Centrosaurus apertus, this ceratopsian skeleton (YPM 2015) was collected by Barnum Brown on the American Museum of Natural History’s extremely productive expeditions to the Belly River region in Alberta. I’m not sure when YPM acquired the fossil (presumably in a trade), but it was mounted and on display by 1929. At some point during the development of the fossil mammal hall, Lull became enamored of half-mounts like this one, in which the animal appears bisected along its sagittal line. Half the skeleton is assembled on one side, while a fleshed-out model is visible on the other. Several mammal specimens at YPM are displayed this way, but the Centrosaurus is the only dinosaur.

Lull discusses the choices made in reconstructing Centrosaurus at length in his 1933 monograph on ceratopsians. He describes the relief-mounted Centrosaurus at AMNH as an imperfect representation of the animal’s life appearance because it preserves the death pose it was found in. In contrast, the YPM version is reconstructed in a three-dimensional standing posture. Lull specifically points to his Centrosaurus‘s nearly straight neck and sprawling forelimbs (with the humerus nearly horizontal) as superior to the AMNH presentation. The issue of ceratopsian forelimb posture is still not completely resolved, but there is probably some truth to Lull’s sprawling reconstruction.

The life-reconstruction side of Centrosaurus, as figured in Lull 1933.

For the fleshed-out portion of the mount, Lull directed the artist to match the musculature and skin texture of iguanas and alligators. A loggerhead turtle was referenced for the mouth and beak. Lull chose to give the small processes on the lower edges of the frill a horny sheath, rather than the fleshy look popularized by Charles Knight. Overall, the life restoration is on the lean side compared to our modern understanding of ceratopsians, but many details—including the digitigrade fingers and forelimb posture—have held up well.

Next time, we’ll look at how historic specimens like Brontosaurus, Stegosaurus, and Deinonychus might be modernized for the new version of the hall.